This invention relates to colloidal size particulates containing particles of an inorganic material and to thermoplastic elastomers containing such particulates.
Metals, metal oxides, pigments, fillers and other inorganic particulates that tend to agglomerate are often coated with or encapsulated in hydrophobic polymers. Methods for preparing colloidal size hydrophobic polymers particulate having discrete particles of an inorganic material dispersed therein are disclosed in U.S. Pat. No. 4,421,660, which is incorporated herein by reference.
Thermoplastic elastomers are typically ABA or AB(BA).sub.n block polymers in which the A block is a thermoplastic material while the B block is an elastomeric material, and n has a value of 0 or greater. See, for example, U.S. Pat. Nos. 3,265,765 and 4,427,837. Because of the thermodynamic incompatibility of the A and B blocks, separate phases of thermoplastic material and elastomeric material form in which the thermoplastic component is dispersed in the elastomeric phase. Such a material exhibits a reversible network structure or domains in which an elastomer exhibits a high tensile strength. Unfortunately, considerable loss of tensile strength of the thermoplastic elastomers occurs when said thermoplastic elastomers are subjected to repeated heat treatment.
In view of the deficiencies of the prior art it would be highly desirable to provide an effective and efficient means for providing thermal stability (as for example, a nonyellowing characteristic) to thermoplastic elastomer materials which stability does not undergo significant degradation over time or over repeated thermal stress.